The communications industry is rapidly changing to adjust to emerging technologies and ever increasing customer demand. This customer demand for new applications and increased performance of existing applications is driving communications network and system providers to employ networks and systems having greater speed and capacity (e.g., greater bandwidth). In trying to achieve these goals, a common approach taken by many communications providers is to use packet switching technology in packet switching networks of various topologies.
A Virtual Private LAN Service (VPLS) is typically built with a full-mesh of Ethernet pseudowires among Multiprotocol Label Switching (MPLS) Provider Edge (PE) routers that are part of a given layer-2 broadcast domain. A VPLS PE emulates an Ethernet bridge by performing data-plane MAC learning against traffic arriving over the pseudowires and local interfaces. Provider Backbone Bridging (e.g., IEEE 802.1ah) defines a hierarchy of bridging devices that includes provisions to scale up the number of services that can be multiplexed into a single Backbone VLAN.